Glossary term: 密度
Description: 密度是物质或物体的一种物理特性,表示了其体积与质量的关系。密度越大,单位体积的质量就越大。物体的平均密度是其总质量除以总体积。在国际单位制(SI)下,其单位是千克/立方米(kg/m3)。
在太阳周围的银河系区域内,密度的数值可从星际气体的约10-20 kg/m3变化到中子星内部的超过1017 kg/m3。
地球上常见的密度数值介于这两个极端之间,例如铁的密度约为7800 kg/m3,水的密度约为1000 kg/m3,在海平面附近、围绕着我们的空气密度略高于1 kg/m3。
宇宙不仅包括恒星、行星和星系中的气体,还包括星系之间和星系团之间相对空旷的空间。因此,宇宙中物质的平均密度约为10-27 kg/m3。
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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher The translation of this term and its definition is still awaiting approval
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